Tube couplings are used to join tube ends to form a continuous fluid passageway. Often this joining is done in connection with a production operation. The time it takes to perform the coupling is important as is the integrity of the connection.
In commercial production today is a quick connect coupling as shown in U.S. Pat. No. 4,055,359 assigned to the assignee of the present invention, the contents of which are hereby incorporated by reference. It provides a simple, relatively inexpensive, and totally reliable coupling for an air conditioning line. It includes an expandable circular spring loosely and substantially coaxially held within an annular cage mounted on a first tube, and a second tube to be telescopically mounted on the first tube and including a flared end which cams under the inside diameter of the spring as the second tube is being inserted upon the first tube. As the second tube is brought home in the coupling, the flared end passes the spring allowing the spring to contract radially onto the tube within the cage.
A special tool is needed to disassemble the coupling for service-related reasons. The special tool slips over the second tube and includes an inclined lip which is directed toward the spring expanding it to an inside diameter greater than the flared end of the second tube, at which point the second tube may be retracted. Over a long period of service, or particularly extreme operating conditions, the internal cavity of the cage can become impacted with foreign material thus making it difficult to disassemble the coupling.
There is also known a quick connect coupling as shown in U.S. Pat. No. 5,039,139, assigned to the assignee of the present invention, which avoids any disassembly difficulties which might be caused by impacted foreign material within the case. It also includes a cage structure which provides a clear view of the assembled coupling at a point where the locking means on the cage of the first tube engages the back side of the flared end of the second tube. It is constructed of a substantially single spring steel clip, with the spring steel locking tabs being formed by a separate staking operation performed on the spring steel cage. The coupling is disassembled by means of the same tool as afore described in connection with U.S. Pat. No. 4,055,359.
The present invention offers the more important advantages of the couplings shown in the aforementioned U.S. Patents. The cage member can be formed on a relatively low tonnage press as in the case with U.S. Pat. No. 4,055,359. Also, the cage includes a plurality of individual locking tabs radially spaced about the cage which function in a manner very similar to the individual locking tabs as shown in U.S. Pat. No. 5,039,139.